1. Field of the Invention
The present invention relates to a watertight cap which is attached to an electric connector of an electronic endoscope so as to make the electric connector watertight in order to prevent a cleaning liquid from entering when cleaning the electronic endoscope.
2. Description of the Related Art
An electronic endoscope for medical use has a solid-state imaging device, which is arranged at the distal end of the insertion part and is connected to an electric connector through a multi-cored cable. The electric connector is provided at the end of a flexible cable, which is extended from a hand control part of the endoscope. A subject image which is captured through the solid-state imaging device is displayed on a monitor by connecting the electric connector with an image processing device called a processor.
The endoscope is immersed in a cleaning liquid after every use in order to be cleaned, but because the electronic endoscope has the electric connector, the electronic endoscope is cleaned while a watertight cap is attached on the electric connector.
FIG. 7 is a semi-section view showing a conventional watertight cap 1 being attached to an electric connector 2. The watertight cap 1 has a click ball 4 and an O-ring 5 provided to a cylindrical part 3, which is pushed into a space between a shell 6 and a release sleeve 7 of the electric connector 1, whereby the click ball 4 engages with a receding part 8, which is formed on an outer periphery of the shell 6. A that time, the watertight cap 1 is watertightly attached on the electric connector 2 by pressing the O-ring 5 against the outer periphery of the shell 6. Connector pins 2A of the electric connector 2 are thus prevented by the watertight cap 1 from getting wet with the cleaning liquid, and the electronic endoscope is cleaned in that state.
However, the conventional watertight cap 1 still has a problem in that the connector pins 2A may get wet with the cleaning liquid when detaching the watertight cap 1 from the electric connector 2. This problem occurs for the following reason. In the structure of the watertight cap 1, it is difficult to discharge the cleaning liquid flowing into the space 9 between the cylindrical part 3 and the shell 6. While detaching the watertight cap 1, the cleaning liquid left in the space 9 follows the cylindrical part 3 and is dragged out to the end of the shell 6, then the cleaning liquid enters from the end into the inside of the shell 6 and reaches the connector pins 2A.
The present invention has been developed in view of the above-described circumstance, and has as its object the provision of a watertight cap for a connector of an endoscope which can prevent the connector pins from getting wet with a cleaning liquid at a time of detaching the watertight cap.
In order to achieve the above-described object, the present invention is directed to a watertight cap which is detachably attached to a connector of an endoscope, the watertight cap comprising: an external cylinder having an engaging part being detachably engaged with an outer periphery of a shell member provided around a connector pin of the connector; and an internal cylinder arranged inside the external cylinder, an end of the internal cylinder being closed, the internal cylinder having a seal member being pressed against an inner periphery of the shell member, wherein a discharge hole opening to outside is formed between the external cylinder and the internal cylinder when the watertight cap is attached on the connector.
According to the present invention, the cleaning liquid flows into the space between the shell member of the connector and the external cylinder but does not enter into a side of the connector pin since the internal cylinder and the shell member are sealed, and the cleaning liquid is discharged to the outside of the watertight cap through the discharge holes, which are formed between the external cylinder and the internal cylinder. Thus, the watertight cap of the present invention can prevent the connector pins from getting wet with the cleaning liquid at the time of detaching the water cap because the cleaning liquid is not left in the space between the shell member and the external cylinder.
Preferably, the shell member of the connector comprises a release sleeve arranged outside thereof for releasing an engagement between the shell member and the engaging part of the external cylinder; the external cylinder has an external form having a small diameter part except the engaging part; and a discharge passage is formed between the small diameter part and the release sleeve. Hence, the watertight cap of the present invention can discharge the cleaning liquid flowing into the space between the external cylinder and the release sleeve to the outside of the watertight cap through the discharge passage. Thus, the watertight cap can prevent the connector pin from getting wet with the cleaning liquid at the time of detaching the watertight cap.